Rotary duplicating machine



vvided with a master copy,

- of the moistening roll Patented Apr. 22, 1941 NTT OFFICE 'ROTARY DUPLICAIIIIG MACHINE `Roscoe R. Bockhill, Milwaukee. Wis. Application December 6, 1939, Serial No. 307,843

z claim.. (ci. sir-s1) This invention relates to duplicating machines of the liquid or spirit type, in which a moistened worksheet is impressed upon a cylinder procontaining subject matter produced in soluble copy ink.

One ofthe greatest dimculties encountered in machines of the foregoing type is to obtain proper uniform moistening of the worksheet, in order to produce uniform copies of desired impression.

In co-pending application for Letters Patent,

No. 271,971, filed May ing diiliculty has been overcome to a. large extent by intermittent operation of a roller moistening mechanism. incorporating a hard squeegee lensth, one of said rollers being formed4 oi' im- 5, 1939, th'e foregoroll for distributing and removing excess'iiuid rom the moistening roll. However, in actual practice it developed that from a manufacturing standpoint itwas practically impossible to obtain perfect contact between two hard rolls sufsurface sreater areas, resulting in deeper points to produce non-uniform copies.

Also, because moistening roll, it initial operation of ciently meisten the worksheet, with the result that the leading end of the sheet received a lighter impression than the following portion, making the copy non-uniform. l Several theories may be advanced in explanation of the foregoing result, one being that rapid starting of the moistening roll has a tendency to break the capillary attraction between the duid and smface of the roll, with the result that lnsumcient moisture is retained by the surface for transmission to the worksheet until such time as the iiuid starts to of the moistening roll, thus .causing was foundv that duringthe v now in the' direction of movement of the roll.

Also, it might be said that milicient iluid is accumulated at the point of contact between the moistening roll and squegee ro1ler, to insure suiiicient retention. oi' moisture on the surface of the moistening roll. At-any rate. the fact remains that in the use of hard moistening and s quegee rollers, insuillcient moisture is transferred to the' worksheet during initial operation of the moistening mechanism.

Therefore, the present invention has primarily for its obiect to overcome the foregoing ,objections by the provision of a moistening device of the driven type, consisting ofl twol rollers conthe moistening roll moistening of the worksheet lin certain v impressions at those the roll, it failed t0 slim;-

uniformly remove excess iiuid from the one another throughout the entire pervious yieldable material, suchlas rubber, syn, thetic rubber. or similar composition. whereby the rolls cooperate to provide uniform distribution of the uid, and elimination of excess fluid.

Incidental to the foregoing, i object of the invention is to provide a vmoistei'iing mechanism of the character described comprising a hard moistening 'roll partially,.sub' merged in. fluid, and in contact with a squeegee roll formed of yieldable impervious material.. and having a 'surface characterized by minute pockets capable of retaining sumcient iiuid to insure proper uniform moistening of the moistening roll at various speeds of rotation, ticularly upon initial ins device. y

With the above and other'obiects in view whichwill appear as the description proceeds, the invention combination. stantially as starting of the moistencabeing understood that such changes in the preof the intermittent drive of the in machines of cise embodiment of the herein disclosed inven. tion may be made as' come within the scope ofthe claims. In the accompanying drawing is illustrated one complete example of the physical embodivment of the present invention, constructed according to the best mode so far devised for the practical application of In the drawing: The single illustration in the accompanying drawing is a fragmentary longitudinal section through a duplicating machine embodying the present invention. which may be incorporated various structures without affecting the operation or principles thereof.

Referringnow more particularly'to the accompanying drawing, the numeral i designates generally a casing consisting of spaced side walls 2 connected by table 4 for reception of astack separately fed, either manually or comprising the subject matter of the present inv vention.

Journaled within the casing', and continuously driven by suitable means, either manual or power-actuated, is a-platen cylinder t for -reception of a master copy. A pressure roll Lin contact with the platen cylinder, serves to impress the worksheets against the master copy, and draw the same through the moistening a more specinc,`

resides in the novel construction, y and arrangement of parts, subhereinafter described, and' more particularly deilned by the appended claims, it

the principles thereof.

mechanism 6, subsequent to initial operation of ior the reception of uid to be transmitted to the worksheet for dissolving the ink contained on the, master copy. Journaled in end brackets iu carried by the trough u, and positioned within the trough for partial submersion in the duid contained therein, is a moistening roll ii, which contacts a squeegee roll i2, slidably journaled in brackets iii, and yieldably held against the moistenlng roll hy suitable springs i3. Positioned above the moistening roll ii, and in conl tact therewith is a frictional feed roller it Jlournaled in the end brackets it, and provided at one end withc a disc id, preferably formed of Aiibre or other non-metallic material, andoperatively engaged by a tooth sector i6 rotatable with the platen cylinder S.

.d hood ii carried fby the side walls 2 of the casing extends over the moistening mechanism to protect the same against dirt, and also pre vent accidental insertion of `the oper'ators hand into the moistening rolls. The forward wall i@ of the hood isinclined downwardly, 'and terminates in a lip iii, that cooperates with the inner end of the supporting table il, to form a throat for guiding worksheets to the bight between the moistening roll ii and the feed roller I4. In that form of the invention illustrated, the moistening roll ilv is preferably formed of hard, smooth material, either metal or suitable composition, while the squeegee roll i2 is formed `of impervious" yielda'ble material, such as rubber,

` synthetic rubber, or composition having similar characteristics, `the surface of they roll being slightly rough in its iinish to provide minute pockets for receiving and retaining moisture as a result of its contact with the moistening roll ii.

From the foregoing explanation considered in connection with the accompanying drawing, it'

is .thought that the operation of the invention will be readily apparent, in that the worksheets are fed to the bight formed Ibetween'the moistening roll Ii. and the feed roller M. The mechaby the pressure roll 1 to reproduce the subjectcontained on the master copy.

It might also be explained that the intermittent drive of the `feed roller It is so timed that the roller is operated only when in contact with a worksheet. Consequently, no moisture or uid from the roll ii is transmitted to the feed roller at any time. Obviously, because'of the pressure of the feed roller Il upon the moistening roll Il,

'drive will be imparted to the latter upon rotay tion ci the feedl roller, and during rotation of the moisteningroll, fluid is picked up from the trough and carried to the squeegee roll i2, thatA serves not only to uniformly distribute uid over the surface of the moistening roll, but also remove through squeezing action excess `uid.

As heretofore explained. it was found in the use of a hard squeegee. roll, that it` was practically impossible to obtain a perfect contact between the squeegee roll and the moistening roll, and also it was impossible to retain sufilcient moisture upon the surface of the moistening roil' during its initial operation. The present squeegee roll formed of yeldable impervious materlal entirely 4overcomes the ioregoing objections, in that its yieldability insures perfect contact regardless ci irregularities in either roll; and at the same time, because .of the character of the surface of the squeegee roll, suicient fluid is retained by it to insure proper moistening of the surface of the roll ii at 1l times during its rota'.- tion, and at variable s ds.

in other Words, the minute pockets present in the surface of the squeegee roll are capable of retaining and transmitting suiilcient moisture to the surface oi the roll il at the point of contact with the squeegee roll, which would not be true ci hard rolls designed to provide a nat surface of contact.

it will be apparent irom the foregoing that exceedingly simple and emcient means have been provided for moistening worksheets of a huid Vduplicating machine, whereby the amount of .A moisture can be accurately controlled and evenly distributed over the entirework sheet to obtain a uniform and clear copy.

I claim:

l. in a duplicating machine of the class described, a sheet moistening mechanism comprising, a duid trough. a moistening roll of hard,

smooth material positioned in saidv trough and partially submerged in the uid, a squeegee roll engaging said moistening roll and formed of yieldable impervious material having minute pockets in its peripheral surface, and a irictional roller engaging said molstening roll for feeding sheets over the same.

2. In a duplicating machine of the class described, a sheet moistening mechanism comprising, a duid trough, a moistening roll of hard, smooth material positioned in said trough and partially submerged in the duid, a squeegee roll engaging said moistening roll and formed of yieldable impervious material having minute exposed pockets in its peripheral surface, a frictional iced roller engaging said moistening roll to Ifeed sheets over the same, and means for intermittently rotating said feed roller only when the same is in engagement with a work sheet.

ROSCQE'R. RGCKiiILi... 

